The present invention relates to an adhesive article with a failure mode that minimizes damage to the substrate surface and a method of using the same. The present invention also relates to an adhesive article that can be removed in a reverse peel mode without damaging the substrate.
Adhesives provide a convenient and low cost way of mounting various structures, such as picture hangers or utility hooks, to walls and other substrates. The nature of adhesives is such that there is often a possibility of damage to the substrate (wall) when a substantial load is applied to the structure. If the load that is applied to the structure exceeds the weight rating of the structure, or adhesion to the substrate is weak, there is a high probability that a peel mode failure will occur. During a peel mode failure, there is a likelihood of wall damage, typically at the bottom of the structure.
While not being bound by theory, it appears that FIGS. 1-3 illustrate the failure mode, as best understood, of conventional adhesives used to attach articles to walls. As illustrated in FIG. 1, hook 20 is attached to substrate 22 by an adhesive layer 24. Load 26 creates a tensile load that produces a peel force 28 near the top of the hook 20 and a compressive load 30 near the bottom of the hook 20. That is, the load 26 creates peel or cleavage de-bonding at the top of the hook 20. As illustrated in FIG. 2, peel force 28 causes the hook 20 to separate slowly from the substrate 22 near the top of the hook 20. As the hook 20 separates from the substrate 22, a pivot point is created generally in the region 32 near the bottom of the hook 20, increasing the compressive load 30 and the adhesion in the region 32. At some point during the delamination process, the hook 20 makes a transition from compression to peel/cleavage in the region 32. Since the surface area of the interface between the adhesive layer 24 and the substrate surface 34 in the region 32 is relatively small, there is a high probability of failure at the surface 34.
As a result of the increased adhesion in the region 32, damage 36 can be caused to the substrate surface 34, as illustrated in FIG. 3. Portion 38 of the substrate surface 34 typically remains bonded to the adhesive layer 24. Where the substrate surface 34 is paint, wallpaper, wallboard, or a variety of other interior surfaces, the cost of repairing the damaged area can be considerable. In some situations, even a small amount of damage may require the entire wall or room to be repainted.
It is therefore desirable to provide an adhesive article with a failure mode that minimizes damage to the substrate surface. It is also desirable to provide an adhesive article that can be removed from the substrate in reverse peel mode without damaging the substrate.
The present invention relates to an adhesive article adapted to attach structures to substrates and a method of using the same. The present invention also relates to a mounting system for a substrate using the present adhesive article.
The present adhesive article permits the use of a high-strength adhesive to attach structures to substrates, with a failure mode that minimizes damage to the substrate surface. The present adhesive article can either be peel removable or stretch releasing. In some embodiments, the peel removable nature of the adhesive article flows from reduced adhesive properties arranged in the desired direction of peel. In these embodiments, the properties that provide the peel removable nature of the adhesive article also minimize the damage to the substrate surface.
In one embodiment, the adhesive article comprises an adhesive layer having a first adhesive region and a second adhesive region. The first adhesive region is adapted to attach a top portion of the structure to the substrate. The second adhesive region is adapted to attach a bottom portion of the structure to the substrate. The second adhesive region comprises reduced adhesive properties.
In one embodiment, the adhesive article comprises a stretch releasing adhesive tape. The stretch releasing adhesive tape includes a pull-tab adjacent to the second adhesive region.
In another embodiment, the adhesive layer comprises a plurality of adhesive regions with progressively reduced adhesive properties. In another embodiment, a single adhesive region comprises progressively reduced adhesive properties, such as by changing the surface area of the adhesive regions.
In one embodiment, the second adhesive region comprises a surface area greater than or equal to about 22% of a surface area of the adhesive layer. In another embodiment, the second adhesive region comprises a surface area more than about 22% of a surface area of the adhesive layer. The second adhesive region can be selected from the group consisting of release liner material, repositionable pressure sensitive adhesive, polymeric film, paper, scrims, nonwoven fabrics, powder, ink, and low adhesion backsize material.
The present invention is also directed to a mounting system for a substrate. The structure may be a variety of articles, such as hooks, picture mounting tabs and the like.
The present invention is also directed to a method of attaching a structure to a substrate. An adhesive article is prepared comprising an adhesive layer having a first adhesive region and a second adhesive region. The second adhesive region comprises reduced adhesive properties. The adhesive article is attached to the structure so that the first adhesive region extends distally from a top portion of the structure and the second adhesive region extends distally from a bottom portion of the structure. The first and second adhesive regions are attached with the substrate.
In one embodiment, the adhesive layer comprises a plurality of adhesive regions with progressively reduced adhesive properties. The structure can be removed from the substrate by delaminating the adhesive article in the direction from the adhesive region with the lowest adhesive properties toward the adhesive region with the greatest adhesive properties. In another embodiment, the adhesive layer is a stretch releasing adhesive article with a pull tab adjacent to the second adhesive region.